Reschedule COMPOSITE_EVENTUALLY instead of COMPOSITE_IMMEDIATELY if we miss a browser frame

Reschedule COMPOSITE_EVENTUALLY instead of COMPOSITE_IMMEDIATELY if we miss a browser frame

If we miss a browser frame, reschedule a new COMPOSITE_EVENTUALL, there will be
high latency/jank before the next composite happens, but this will keep the
browser compositor and renderer compositor in sync (low latency mode). While if
we COMPOSITOR_IMMEDIATELY, it could make the browser compositor always one frame
behind renderer compositor (high latency mode).

BUG=379264
TEST=record a trace for the following test:
     scroll on a simple page, first with top control hidden, then transit into showing the
     top control.
     With COMPOSITE_IMMEDIATELY, the latency graph shows that the scroll latency jumps up
     at the point of transition and stays at high latency mode.
     With COMPOSITE_EVENTUALL, the latency graph shows that the scroll latency jumps up
     at the point of transition but comes back to normal after.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=274640

[no sievers, 2014-06-03 17:04:11]

LGTM.

Thanks for looking into this!

https://codereview.chromium.org/310873002/diff/1/content/browser/renderer_hos...
File content/browser/renderer_host/compositor_impl_android.cc (right):

https://codereview.chromium.org/310873002/diff/1/content/browser/renderer_hos...
content/browser/renderer_host/compositor_impl_android.cc:685: // We somehow
missed the last vsync interval, so reschedule.
Maybe put a small comment to say why we schedule for the deadline, like "We
cannot schedule immediately, or will get us out-of-phase with new frames".

[Yufeng Shen (Slow to review), 2014-06-03 18:22:29]

The CQ bit was checked by miletus@chromium.org

[Yufeng Shen (Slow to review), 2014-06-03 18:22:35]

https://codereview.chromium.org/310873002/diff/1/content/browser/renderer_hos...
File content/browser/renderer_host/compositor_impl_android.cc (right):

https://codereview.chromium.org/310873002/diff/1/content/browser/renderer_hos...
content/browser/renderer_host/compositor_impl_android.cc:685: // We somehow
missed the last vsync interval, so reschedule.
On 2014/06/03 17:04:11, sievers wrote:
> Maybe put a small comment to say why we schedule for the deadline, like "We
> cannot schedule immediately, or will get us out-of-phase with new frames".

Done.

[commit-bot: I haz the power, 2014-06-03 18:23:30]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/miletus@chromium.org/310873002/20001

[commit-bot: I haz the power, 2014-06-03 21:50:38]

Change committed as 274640